The present invention is directed, in general, to a method of testing and, more specifically, to a method for reliability testing leakage characteristics in an electronic circuit and a testing device for accomplishing the same.
Reliability of electronic devices, namely traces in semiconductor devices, is of great concern in today""s competitive electronic markets. The reliability of a certain electronic device, however, may not be known until the electronic device is used for a long period of time. For example, it might take up to two years for a particular electronic device to experience reliability issues caused by normal operation.
This lag in time between manufacturing the particular electronic device and the emergence of a reliability issue, is particularly problematic. The lag time tends to drive manufacturers in the electronic industry to continue to manufacture the electronic devices without having the appropriate reliability data. In many instances, the severely delayed reliability data is returned as negative reliability data, and an entire lot of electronic devices may need to be discarded. Discarding the electronic devices causes the manufacturing cost of the devices to increase dramatically, a cost which is ultimately passed on to the consumer.
Currently, in an effort to promptly determine the reliability of the electronic device, and therefore reduce manufacturing cost, manufacturers have begun to use accelerated testing. One form of accelerated testing involves biasing all traces in the electronic device, in an attempt to accelerate the development of electrical leakage between the traces. The biasing scheme is ordinarily conducted in an environment of increased temperature and moisture, which tends to further accelerate the development of electrical leakage between the traces.
After biasing all of the traces for a specified period of time, the electronic device is tested for electrical leakage. Dendrites, which may form across any two traces forming an electrical leakage, are of particular concern, however, any leakage mechanism may be detected. The accelerated testing is particularly beneficial, in that it can determine reliability data relatively quickly, for example, on the order of a few weeks of time, as compared to up to about two years if the reliability is based upon normal operation.
Problems, however, currently exist with the accelerated testing method described above. One problem is the amount of time and effort required to perform such tests. For example, it takes a large amount of time and effort to individually bias each adjacent trace, then subsequently test each trace for electrical leakage against every other trace in the electronic device. Moreover, to test each trace as described above requires that a special high pin count tester, or multiple passes of a lower pin count tester, be used to complete the testing of the entire electronic device. Such a process is also time consuming and expensive. A method for correcting the above problems might include testing only a portion of the conductors. However, while this might save time and effort, it only provides an approximation of the reliability data, and approximations are typically considered inadequate reliability measurements.
Accordingly, what is needed in the art is a method of testing reliability of an electronic device that does not experience the drawbacks experienced by the prior art methods.
To address the above-discussed deficiencies of the prior art, the present invention provides a method for reliability testing leakage characteristics in an electronic circuit and a testing device for accomplishing the same. In an advantageous embodiment, the method includes dividing conductors of an electronic circuit into at least first and second noninterleaved regions having at least two conductors each. The method further includes forming conductor nets by electrically connecting ones of the at least two conductors of the first region to ones of the at least two conductors of the second region, then testing for electrical leakage in the conductor nets.
The foregoing has outlined preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention.